1. Field of the Invention
The present invention generally relates to positron emission tomography imaging systems, detectors, data processing apparatuses, computer readable program products having positron emission tomography imaging programs for user terminals, and methods for positron emission tomography diagnosis, and more particularly, to a positron emission tomography imaging system, detector, data processing apparatus, computer readable program product having positron emission tomography imaging program for a user terminal, and method for positron emission tomography diagnosis, whereby cost for equipment at a user side can be reduced and tolerance against an obstruction can be improved by load-sharing.
2. Description of the Related Art
A positron emission tomography (hereinafter “PET”) apparatus has been used for imaging the internal distribution of a radioactive isotope (hereinafter “RI”) given into an object to be examined. In a diagnostic method in which the PET apparatus is used, first a positron emitting radioactive compound is introduced into the body of the object to be examined by an injection, inhalation, or the like. The radioactive compound introduced in the body of the object to be examined is metabolized and accumulated in a specific portion of the body. At this time, the positron is emitted from the RI tagged for the radioactive compound. The emitted positron and a vicinage electron are annihilated and two gamma ray photons are emitted in opposite directions. An image is reconstructed by computer-processing from information about the detected photons, reconstructed image data in the object to be examined can be obtained. The object to be examined can be diagnosed by the reconstructed image data.
There is a scintillation detector, a semiconductor detector, or the like, as a means for detecting a detect signal in a conventional PET apparatus. Particularly, the semiconductor detector directly detects the gamma ray while the scintillation detector requires two conversion steps, namely converting the gamma ray into light and converting the light to electric signal. Hence, the semiconductor detector has a higher conversion efficiency to an electric signal than the scintillation detector. Furthermore, since a semiconductor cell can independently detect gamma rays, energy resolution and counting efficiency are higher than in the scintillation detector. A technology using such a radiation semiconductor detector is disclosed in Japan Laid-Open Patent Application No. 11-281747, for example.
Meanwhile, the conventional PET imaging system usually has an image reconstruction apparatus, an image display apparatus, or the like in addition to an instrumentation apparatus including the PET apparatus. Furthermore, an image reconstruction algorithm (image reconstruction information) for reconstructing an image in the image reconstruction apparatus is fixed when the apparatus is shipped. Because of this, there may be problems in that the image reconstruction apparatus itself should be changed in a case where the image reconstruction algorithm is changed and that the image reconstruction apparatus cannot be used with the change of the image reconstruction algorithm.
Furthermore, since hardware resources in the above-discussed PET imaging system are extremely expensive, a imaging system wherein separate apparatuses such as a scanner part for scanning the object to be examined, a host computer for reconstructing a medical image from information of the object to be examined that is scanned by controlling the scanner part, a user terminal indicating the reconstructed image, or the like, are connected by a network such as the Internet may be used. In this case, however, since control data in the scanner part are managed in a unified manner at the side of the host computer, it is difficult to change a scan parameter or the like with a user terminal. Furthermore, when the number of the user terminals increases, the load on the host computer increases.